Method of obtaining valuable products from combustible materials



April 24, 1928.

A. H. PEHRSON METHOD OF OBTAINING VALUABLE PRODUCTS FROM COMBUSTIBLE MATERIALS Filed Auz. 13. 1925 Patented Apr. y24, 192s.

UNITED STATES PATENT OFFICE.

ADAM HELMER PEHBSON, 0F STOCKHOLM, SWEDEN, ASSIGNOR TO DUNFOBD t ELLIOTT (SHEFFIELD) LIMITED, OF SHEFFIELD, ENGLAND.

METHOD Ol OBTAINING VALUABLE PRODUCTS FROM COMBUSTIBLE MATERIALS.

Application led August 13, 1823, Serial No. 657,242, and in Sweden lAugust 19, 1822.

The present invention relates to a method of obtaining in substantially large quantities suilicient for commercial use, valuable products, i. e., oil, gas, smokeless fuel, etc., from combustible materials such as coal, shale, peat` wood and the like.

According to the invention I employ a horizontal or inclined rotating or oscillating furnace which is so constructed and arranged as to constitute or form part of a system or series ot' intercommunicating ret'orts or chambers so that each step or stage of the process to which the combustible material (hereinafter termed the charge) is subjected is carried out separately, and the charge is passed through the system or series of intercommunicating retorts or chambers, in consequence of its rotary or oscillating motion, Without the mixing of the different gaseous and other products formed during the process, the said retorts or chambers being heated by air for combustion inside said retorts or chambers introduced in such a manner that it is forced through and permeates the charge during the forward motion of the latter through said retorts or chambers which takes place owing to the rotation or oscillation thereof or by a gaseous or aeriform fluid heated to the required temperature and similarly admitted to the charge in said retorts or chambers or by the heat derived from an electric current. The said retorts or chambers may be provided with central openings in their Walls for charging and discharging purposes and the leading off of the various gases produced during the process.

In carrying out the process the charge is lirst subjected to a drying and pre-treatment process in a retort or chamber provided for the purpose which is kept at a suitable temperature so that mainly only valueless products are formed therein such as carbon dioxide and steam. The charge after having been thus dried and pre-treated is then introduced into another retort or chamber which acts as a distillation retort Where oils and tars are disassociated. The gases formed during the distillation are, furthermore, not diluted by the gases formed in the drying and pre-treatment retort or chamber which latter gases being valueless, are led off by suitable pipes, so that a gas is obtained in the distillation retort or chamber with a high caloritic value and the condensation (which takes place in a condensing chamber) as well as the refining of the products, is consequently facilitated.

The dried and pre-treated charge may second retoit or chamber Working at somewhat increased temperature, Where another step or stage in the process is carried out, and so forth into a third retort or chamber and so on, all Working under a gradual -increase of tem erature where the various steps or stages in t ie process of fractional distillation are carried out and finally, after complete dry distillation has 'taken place the charge is introduced into a cooling retort or chamber. In this process (i. e., fractional distillation) the gaseous products formed in the various retorts or chambers above mentioned should be taken out separately and not be mixed, for which purpose the various retorts or chambers are so arranged that the gases evolved can be drawn off Without hindrance to the passage of the charge from one retort or chamber to another. The said retort or chamber in Which the pre-treatment takes place may be heated directly by means of Warm air or heated waste gases, and may be either stationary or rotating. The other retorts or chambers are arranged to rotate or oscilla-te and in these the heating is accomplished either by the introduction into the charge of warm gases or through partial or complete combustion of the charge therein, or by electric heating. If it is desired that the ash contents of the charge should be removed, the temperature of the retort or chamber in which the final step or stage of the process takes place is kept sufficiently high to smelt the ash with a suitable flux which is run olf in liquid form. The sulphur contents may be removed from the charge by adding iron ore or the like to effect the fixing of the'sulphur. The accompanying drawings show diagrammatically some ty aical retorts or chambers suitably arrange for carrying out the said process.

Figure 1 is a vertical sectional vlew of a retort for practicing the invention. Figure 2 is a vertical sectional view of a modified form of retort. Figure 3 is a vertical sectional view of a retort for generating gas.

Figure 1 shows anv arrangement of retorts or chan'ibers suitable for the dry distillation ofcoal and comprises a rotary retort or chamber 1 for drying and pre-treating the coal; a stationary transfer chamber 2, a rotating dry distillation retort or chamber 3, communicating with the stationary trans-v fer chamber 2 at one end; and a stationary discharge chamber 4 from which the discharging of the gaseous products and the treated coal takes place.

Figure 2 shows a modification of the arrangement in Figure 1 in which the drying and pre-treatment retort or chamber mstead of being separate from the distillation retort or chamber is combined therein.

Figure 3 shows a retort or chamber intended mainly for the generation of' gas alone.

The coal to be treated is introduced through feed apparatus 5 :into the rotary retortor chamber 1 and is fed forward owing to the rotation thereof. In this retort or chamber the coal is dried and pretreated by the heat derived from gas burnt in a burner 6; and steam and carbon dioxide are given off, which are carried away through a chimney 7, in a stationary chamber 8. The coal after having undergone the pre-treatment falls into the stationary transfer chamber 2 from which it is conducted by suitable feed apparatus 9 into the neck 10 of the distillation retort or chamber whence it passes into the distillation retort or chamber 3, where the dissociation (dry distillation) takes place. The required heat for the distillation is obtained either from a heated gaseous or aeriform fluid or by the partial combustion of coal. The said gaseous or aeriform fluid is introduced into the distillation retort or chamber from a gas box or chest 11 fixed thereto and rotating therewith the fluid passing through openings, slits or tuyrcs 12 which are provided with automatic regulators such as ball valves 13 for controlling the introduction of the said gaseous or aeri't'orm fluid into the coal, although, if desired, the said regulators may be arranged to introduce the gaseous or aeriform fluid above the coal, that is, at the upper part of the distillation retort or chamber. The said gaseous or aeriforin fluid is supplied to the box or chest 11 through a' pipe 14 which terminates in a casing 14Cx surrounding the neck 1() and communicating with the box or chest v11 in such manner as to allow the rotation of' the distillation retort or chamber 3 to take place. The gaseous products' evolved in the distillation retort or chamber 3 enter the Vstationary chamber Il'from which they are conducted through a pipe 15 to a condenser (not shown). The solid residues (semicoke) are removed through an ejector apparatus 16, as required, to a. suitable cooling chamber (also not shown). It will be observed that the material undergoing treat' ment in the furnace 4chamber is maintained at a constantand predetermined depth throughout the length of the furnace. so that the resistance it ofl'ers to the flow of the aeriform or gaseous fluid is such as to cause the latter to spread out as it were over a whole mass of the charge, and as a consequence thoroughly permeate the same.

Referring now to Figure 2 the pre-drying retort or chamber instead of forming an external unit communicating with the distillation retort or chamber as shown in Figure l is combined within the distillation retort or chamber and is in the form of a long tube 1T co-axially arranged .inside the dis! tillation retort. or chamber 3 with which it rotates. The charge is fed into the interior of said tube by a feed apparatus 18 and reaches the interior of the distillation retort or chamber 3 through the' inner open end ofthe chamber 10 through which chamber and a pipe 15 communicating therewith the gaseous products are discharged. The

arrangements for the supply of gaseous or.

aeriforin fluid are substantially the same as previously described. The distillation retort or chamber 3 is in this case provided with an elongated neck or trunk 19 which communicates with a stationary chamber 4 from which the removal of the solid residues (semi-coke) takes place. In an arrangement of this kind the outgoing or discharged solid residues pre-heat the charge which is preferably dried and pre-treated before hand as it isfed in through the tube 17. In other respects the process is carried on in the same manner as described with reference to Figure 1.

Referring now to F igure 3 which shows apparatus mainly for the generation of gas, the rotating retort or chamber 2() (which in this case acts as a gas generator) is provided with a relatively long neck or trunk 21, which communicates with a stationary chamber 22. where the charge feeding apparatus 23 is situated. said feeding apparatus operating to feed the charge into said neck or trunk 21. At the opposite end the gas generator is provided with a shorter neck 24 which communicates with another stationary chamber 25 where the spent charge or ash is ejected. Both stationary chambers 22 and 25 are provided with pipes 26 and 27 for the discharge of the gaseous products, the aeri-v forln or gaseous fluid being admitted through t-uyres 28 arranged in the end of the gas generator. The tn veres 28 are. as hcreinbefore stated. provided with automatic regulators 29 and are connected with a box or chest 30 for the gaseous fluid which exlll' tends over and embraces the neck or trunk 21. Connected with the box or chest 30 is a pipe 31 Vfor supplying the gaseous` or aeriform fluid the connectionbetween these parts being such as to allow the rotation ot' the gas generator or producer 20 and the neck or trunk 2l to take p lace. 'l`he charge is supplied in a suitabl dried and pre-treated condition by the feet ing apparatus 23 and isv in consequence of the rotation of the gas generator or producer fed for 'ard through the neck or trunk 2l into the interior thereof. During the passage.v` the dissociation of the charge takes place b the aid of a requisite volume of gas from the generator,- which gas` together with the volatile products are carried through tube 26 to a. condenser (not shown). The solid residue (semi-coke) is fed forward into the generator and burnt. with aeriform Huid introduced through the tuyres 28. The charge can also be introduced into the generator in its original condition i. e., Without undergoing a pre-treatment in which case the volatile products are carried away -with the producer gas.

It will of course be obvious that all the 'oints between movable and stationary chambers must be made effective against gas leakage.

Although I have described and shown the furnace as forming part of a system or series of intercommunicating retorts I wish it to be understood that the furnace and the said intercommunicating retorts may he made as a single unit if so desired.

lVhat I claim and desire to secure by Letters Patent of the United States is 1. In a rotating or oscillating chamber the method of heat treating solid carbonaceous material which consists in continuously introducing the material into the chamber through an openingr in one end thereof, tumbling, rolling or agitating the material by the actuation ot said chamber, introducing gaseous fluid beneath the surface ot' the material thereby heating the same. maintaining the depth of the material uniform throughout, said chamber and at such a depth that said gaseous fluid is caused to thoroughly permeate said material throughout its mass and removing the residues or product through an opening in the opposite end of said chamber to thatI at which the material enters.

2. In a rotating or oscillating chamber the method ot' heat treating solid carbonaceous material which consists in continuously introducing said material into the chamber through an opening in one end thereof, tumbling, rolling or agitating the material by the actuation of said chamber, introducing gaseous iiuid beneath the surface ot the material thereby heating the same, removing the residues or product through an opening in the opposite. end of said chamber to that at which the material enters and maiutaining the level of said material at the same level as that of said openings during the heat treatment.

3. In a rotating or oscillating chamber the method of heat treating solid carbonaceous material which consists in continuously introducing said materia-l into the chamber having a lateral coaxial extension at one end ot' said chamber, the material being introduced through said coaxial extension, tumbling, rolling or agitating the material by the actuation of said chamber, heating said introduced material by heat obtained from gaseous fiuid which is caused to permeate said material, removing the residues or product through another lateral coaxial extension at the opposite end of the chamber to that at which the'material enters and niaintaining the level of said material in the chamber atl the same level as that ot' said lateraly coaxial extensions during the heat treatment.

4. In a rotating or oscillating chamber the method of heat treating solid carbonaceous material which consists in continuously introducing said material into the chamber through an opening in one end thereof,-

tumbling, rolling or agitating the material by the actuation of said chamber, heating said introduced material by 4heat `obtained from gaseous fluid`ivhich is caused to permeate said material, removing the residues or product through an opening in the opposite end of said chamber to that at which the material enters, maintaining the level of said material at the same level as that of said openings during the heat treatment and preheating said material during its passage to said chamber.

5. In a rotating or oscillating chamber the method of heat treating solid carbonaceous material which consists in continuously introducing said material into the chamber through an opening in one end thereof, tumbling, rolling or agitating the material by the actuation of said chamber, heating said introduced material by heat obtained from aeriform iiuid which is caused to permeate said material, removing the residues or product through an opening in the oppositel end of said chamber to that at which the material enters, maintaining the level of said material at the same level as that of said openings during the heat treatment and preheating said material during its passage to said chamber by aeriform fluid at a predetermined temperature.

6. In a rotating or oscillating chamber the method of heat treating solid carbonaceous material which consists in continuously introducing said material into the chamber through an opening in one end thereof, tumbling, rolling or agitating the material by the actuation of said chamber,

, heating said introduced material by heat 7. In a rotating or oscillating chamber` the method of heat treating solid carbonaceous material which consists in continuously introducing said material into the chamber through an opening in one end thereof, tumbling, rolling or agitating the material by the actuation of said chamber` heating said introduced material by heat obtained from aeriform fluid, which is caused to permeate said material, removing the residues or product through an opening in the opposite end of said chamber to that at which the material enters, maintaining the level of said material at the same level as that of said openings during the said treatment and preheating said material during its '(passage to said chamber by aeriform lui obtained therefrom and acting indirectly upon said material.

8. In a rotating or oscillating chamber the method of heat treating solid carbonaceous material which consists in continuously introducing said material into the chamber through an opening in one end thereof,

tumbling, rolling or agitating the material by the actuation of said chamber, heating said. introduced material b heat obtained from the gaseous iluid which is caused to permeate said material, removing the residues or product through an opening in the opposite end of p said chamber to that at which the material enters, maintaining the level of said material at the same level as that of said openings during the heat treatment, preheating said material during its.

passage to said chamber and preventing the gases evolved during the preheating from mixing with those evolved during the main heating of the material in said chamber.

AnAM HELMER PEHRsoN. 

